New ocean forming in African desert

November 4, 9:59 AMScience News ExaminerMeg Marquardt

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The rift in Afar, Ethiopia (credit University of Rochester)

In 2005, a rift opened in the middle of a desert in Ethiopia. The 35-mile-long tear was met with controversy when some scientists claimed it was caused by the Africa continent being pulled apart by opposing tectonic plates. But now it has been confirmed: scientists are watching an ocean in the making.

The confirmation was found by looking underneath the rift. There, volcanic activity is hard at work causing sudden breaks in tectonic plates. This is “nearly identical” to what happens at the bottom of the ocean, and scientists have agreed that the tear is likely the start of a new body of water.

Published in Geophysical Research Letters, the research is support of a new way of thinking about tectonic plates. For quite some time, scientists have assumed the plates only move in small increments, and not in large, sudden breaks. But many now view the rift as proof of the latter theory.

"This work is a breakthrough in our understanding of continental rifting leading to the creation of new ocean basins," says Ken Macdonald, professor emeritus in the Department of Earth Science at the University of California, Santa Barbara, and who is not affiliated with the research. "For the first time they demonstrate that activity on one rift segment can trigger a major episode of magma injection and associated deformation on a neighboring segment. Careful study of the 2005 mega-dike intrusion and its aftermath will continue to provide extraordinary opportunities for learning about continental rifts and mid-ocean ridges." [University of Rochester]

Studying the bottom of the ocean has proven a challenge for geologists, but the Ethiopian rift, which opened to 20 feet in width in days, is likely to become a new flocking place for researchers hoping to understand how ocean ridges form and establish. In addition, the location will offer data to help build the fast-moving tectonic plates theory.

Atalay Ayele, professor at the Addis Ababa University in Ethiopia, who led the investigation established that the rift was not caused by a series of small earthquakes overtime, but rather split quickly along its whole length due to volcanic events which forced magma through the middle of the rift.

"We know that seafloor ridges are created by a similar intrusion of magma into a rift, but we never knew that a huge length of the ridge could break open at once like this," says Cindy Ebinger, professor of earth and environmental sciences at the University of Rochester and co-author of the study. "Seafloor ridges are made up of sections, each of which can be hundreds of miles long. Because of this study, we now know that each one of those segments can tear open in a just a few days." [UR]

Research continues around the rift, which continues to undergo volcanic events. Since 2005, 12 other events have occurred, further pulling apart the tear in the desert. Learning the dynamics of the system will not only teach scientists how continents are ripped apart and how oceans form, but it may also lead to a better way to predict such events whose sudden nature pose a great danger for populated areas.